1. Field of the Invention
The invention relates generally to the field of integrated circuit (IC) device packaging technology and, more particularly, to techniques for providing support to a ball grid array (BGA) packages during assembly processes.
2. Related Art
Integrated circuit (IC) dies are typically mounted in or on a package that facilitates attachment to a printed circuit board (PCB). One such type of IC die package is a ball grid array (BGA) package. BGA packages provide for smaller footprints than many other package solutions available today. A BGA package has an array of solder balls located on a bottom external surface of a package substrate. The solder balls are reflowed to attach the package to the PCB. In one type of BGA package, the IC die is mounted to a top surface of the package substrate. Wire bonds typically couple signals in the IC die to the substrate. The substrate has internal routing which electrically couples the IC die signals to the solder balls on the bottom substrate surface.
A number of BGA package substrate types exist, including ceramic, plastic, and tape (also known as “flex”). In some BGA package types, a stiffener may be attached to the substrate to supply planarity and rigidity to the package. In such packages, the IC die may be mounted to the stiffener instead of the substrate. Openings in the stiffener may be used to allow the IC die to be wire-bonded to the substrate.
Die-up and die-down BGA package configurations exist. In die-up BGA packages, the IC die is mounted on a top surface of the package, opposite of the side to which the solder balls are attached. In die-down BGA packages, the IC die is mounted on a bottom surface of the package, on the same side as which the solder balls are attached.
Various assembly process steps for the BGA package may cause harmful stresses and shocks to the IC die. These process steps include attachment of the IC die to the BGA package, attachment of wire bonds, encapsulation of the IC die and wire bonds for environmental protection, attachment of solder balls to the BGA package, and other steps. As a result of the stress occurring during these processes, the package stiffener may become deformed. The deformation of the stiffener may lead to the formation of cracks in the IC die, potentially rendering the IC die inoperable. Hence, costs in terms of lost money and time may be incurred for repairing and replacing damaged IC dies and BGA packages, among other costs.
Hence, what is needed are improved BGA package assembly processes that reduce stresses and shocks that may harm the BGA package.